Storages for virtual environments, i.e., virtual storage devices, have been used which are storage systems that have volume configurations and storage capacities not restricted by the volume configurations and storage capacities of physical storage devices. A virtual storage device includes an internal real storage unit (also referred to as real SU or, simply, SU) that controls the access to a physical storage device. A processor unit (PU) that manages the real storage unit creates virtual volumes (hereinafter referred to as VDISKs). Physical storage areas of the real storage unit are assigned to the virtual storage areas in the VDISK.
An example virtual storage device will now be described that includes a real SU having four groups of redundant arrays of inexpensive disks (RAIDs) and eight logical units (LUNs) each having a capacity of one terabyte (TB). The virtual storage device provides any number of VDISKs having any capacity, e.g., eighty VDISKs each having a capacity of 100 GB, for a business server used in business systems, regardless of the number and size of real LUNs.
Some virtual storage devices can expand the storage areas of the entire virtual storage devices if the devices need additional storages. For example, the storage area of such a virtual storage device can be expanded in units of a combination of a PU and an SU, which manage the real storage unit. The addition of an extended set consisting of a combination of a PU and an SU to a virtual storage device is referred to as “scaling out.” A virtual storage device that has the ability to scale out is known as a “scale-out virtual storage device.”
The reliability of an entire information processing system can be enhanced in preparation of disasters and system updates through the installation of multiple virtual storage devices at sites geographically remote from each other.
In such a configuration, the virtual storage device used by the business server is installed at a local or primary site, and a backup virtual storage device is installed at a remote or secondary site. The PU of the virtual storage device at the primary site and the PU of the virtual storage device at the remote site are connected with a data transmission line via a switch (SW). In preparation for damage of the local site, the data stored at the local site is duplicated to (backed up at) the remote site through a remote copy (RemoteCopy (RC)) session.
If the local site is damaged by a disaster, the service can be continued through the use of the data duplicated in the remote site. To continue the service, the remote copy session must be deleted. This is because data cannot be written in the VDISK of the secondary site if the remote copy session is active.
FIG. 20 illustrates a site-switching process in a conventional virtual storage system in case a local site is damaged by a disaster.
In Step S101, the local site is damaged in a disaster.
In Step S102, an operation administrator of the information processing system instructs the cancellation of a schedule of remote copy of the virtual storage device with a web GUI or a command line interface (CLI) of a management server at the remote site.
In Step S103, the schedule of remote copy of the virtual storage device at the remote site is cancelled.
In Step S104, the secondary site is designated as a primary site, and the service provided by the business server is resumed using the VDISKs of the latest primary site.
A business server running virtual software, such as VMWare ESXi (trademark), requires resigning (re-registration) for each VDISK to use the data sent to a secondary site through remote copy and resume the service.
The resigning is a process of copying a volume (VDISK) registered as a data store in a virtual storage device and registering the duplicated VDISK as a data store. During the resigning, the identifier of the original VDISK is compared to the identifier of the duplicated VDISK. If the identifiers do not match, the identifier of the duplicated VDISK is rewritten. For example, ESXi uses VDISK identifiers that conform to the format of T11 network address authority (NAA).
NAA conforms to the convention associated with Internet small computer serial interface (iSCSI) node names in the RFC-3980 iSCSI. The NAA identifier contains a serial number unique to VX and a volume number unique to the created volume. The NAA identifier corresponds to a value unique to each volume (VDISK).
The resigning, which must be performed on every VDISK, requires five or more minutes every VDISK. For example, the resigning of 300 VDISKs requires 5 hours 48 minutes and 7 seconds.
A scale-out virtual storage device has several thousands to several tens of thousands VDISKs. Thus, the resigning process is extremely time-consuming, preventing the practical switching of a virtual storage device between sites.